This invention generally relates to security systems where a remote signaling device is used to communicate with a system controller. More specifically, this invention relates to security systems that incorporate random numbers into remote signals, which enhances the integrity and security of the system.
Security systems for protecting vehicles from theft and buildings from unauthorized entry sometimes include remote signaling devices. The remote signaling device is used to cause the system controller to perform some action, such as unlocking the doors of the vehicle or building. While remote activation is a desirable convenience feature, it introduces certain drawbacks and creates the potential for the security system to be overridden or accessed by an unauthorized user.
A significant drawback introduced by remote signaling in security systems is that a potential thief can intercept a signal from the remote signaling device as it is transmitted to the system controller. In systems where the same signal is repeatedly sent from the transmitter, the potential thief simply captures one transmission of the signal and later imitates that signal with an unauthorized transmitter to gain access to and control over the security system. One attempt at overcoming this problem is to provide a remote signaling transmitter with the ability to alter the signal that is transmitted. Many such systems are not sufficiently secure, however, because a potential thief can intercept a series of transmitted signals and later predict what a subsequent authorized signal will be. Therefore, through successive trial and error, a potential thief can gain unauthorized access to and control over the security system.
Prior to this invention a security system with a remote signaling device that is immune from the type of tampering described above, has not been provided.